This project studies several types of instrumentation used either in biomedical and biochemical applications, for purposes of improving their operation and understanding inherent limitations. In a continuing study aimed at optimizing experimental design in NMR experiments, we have produced optimal designs for measurements of spin-spin relaxation times, when there are one or two of these times that characteriz the tissue. These designs reduce the variance of parameter estimates by factors of up to two thirds. A project has been initiated to study the usable degree of data compression of medical images obtained from several modalities. The ultimate goal of this project is to transfer presently-held patient images from their original form to a form which allows digital storage. An initial study wil be conducted to determine the degree of compression which does not compromise image quality. This will involve psychophysical experiments to be performed making use of radiologists at the Clinical Center. As part of this investigation, possible improvements in wavelet-based compression techniques will be tested. A study has been initiated on the use of edge detection schemes to facilitate automatic quantitative analysis of intravascular ultrasound images to quantitatively evaluate the volumetric progression of atherosclerosis. A collaboration has been formed with investigators at the Washington Hospital Center. The results of this study will be implemented and tested at the Center, and if successful, will be applied clinically. Further tests have been performed to validate the use of an electrophoretic model to account for experimentally observed asymmetric peak shapes in gel electrophoresis. The theory, based on the notion of random entanglements o the migrating protein with the gel, has thus far accounted for several surprising experimental observations. Further tests, both experimental and theoretical, are in progress.